If high-density mounting of semiconductor devices is to continue, bare-chip mounting would be ideal. However, quality assurance and handling are difficult in the bare chip state. A packaging method called CSP (chip scale/size package) has been developed to provide a package that has a size when packaged that is close to the chip size. This CSP type of semiconductor device has been developed in various forms; in one of them, a flexible substrate is provided on an active surface side of a semiconductor chip and a plurality of external electrodes are formed on that flexible substrate. With this semiconductor device, the external electrodes are provided within the area of the semiconductor chip, so that it does not have the "outer leads" that extend outward from the side surfaces of the package itself, as in a QFP (quad flat package) or TCP (tape carrier package), for example.
In a CSP type of semiconductor device that uses a flexible substrate, it is known to inject resin between the active surface of the semiconductor chip and the flexible substrate to absorb thermal stresses, as disclosed in, for example, International Publication WO95/08856.
However, various difficulties occur during the resin injection. For example, the resin is injected between the semiconductor chip and the flexible substrate, in other words, into a cramped region between the other components, and thus it is easy for air (air bubbles) to remain therein. If that should happen, the air (air bubbles) could expand at high temperatures and under high humidity, causing cracking. It is also difficult to stop the resin from flowing out from between the semiconductor chip and the flexible substrate.
The invention was devised in order to solve the above described l problems and its objective is to provide a film carrier tape and a semiconductor device, a method of making the same and a circuit board, wherein resin is readily injected in a favorable state between the semiconductor chip and the flexible substrate.